MicroGrid

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C Madhava ReddyEE09G003

April 8, 2023

OutlineIntroduction to MicroGridMicroGrid Operating ModesDriving Factors for MicroGridInterconnected MicroGrids – Power Parks.How MicroGrid deviates from Traditional Distribution

SystemChallenges in MicroGridControl strategiesProtection and SafetyEnvironmental AspectsMicroGrid advantages and disadvantagesFuture scope of ResearchReferences

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Introduction to MicroGridWhat is MicroGrid?MicroGrid is an integrated power delivery system consisting

of inter connecting loads and distributed energy resources

MicroGrid can be operated in parallel with the conventional grid or in island mode(independent)

MicroGrid consists of Fuel cells ,Micro turbine , Reciprocating engines , wind power and PV array systems which are together called Micro sources

Excess Power can be sold to Utility grid or It can Draw surplus power to its loads

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Introduction to MicroGridMicro grid Consists

Distributed Energy Resources(DER)LoadsStorage DevicesControllersPoint of Common Coupling

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Introduction to MicroGridDifferentiation

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Schematic diagram of MicroGrid

MicroGrid Operating ModesGrid Connected Mode: Utility grid is active

Static switch is closed

A,B,C feeders are being Supplied by utility grid and Micro grid

D feeder is supplied byUtility grid only

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MicroGrid Operating ModesIsland Mode:Utility grid is not supplying power

Static switch is open

Feeder A, B, C are being Supplied by Micro sources

Feeder D (not sensitive )is dead from microgrid view

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Driving Factors for Micro GridIncreasing Power demand

Emphasis on Reliability ,Quality, Price of Power

Consumer choice

Transmission constraints driving generation sources closer to loads

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Interconnected Micro grids Practical size of Micro grids is limited to a few MW

For larger loads, it is desirable to interconnect many Micro grids to form a larger Micro grid network called Power Parks

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How MicroGrid deviates from Traditional Distribution SystemMicroGrid (MG) has 2 modes of operation

Its short circuit capability changes when mode of operation changes

MG allows Bidirectional Power flow

MG has power electronics interface, so it can’t provide high levels of fault current for relays

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Challenges in MicroGrid Distribution protection and control practice is largely

incompatible with the MicroGrid concept

Non-conventional generation will require new unit control and protection strategies for successful MicroGrid operation

Supervisory controls will be needed to achieve the full operating potential

Tariff structures are presently incompatible with multiparty MicroGrids

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Control StrategiesIt has mainly 3 types of control levels

Micro Generator controllerMicroGrid central controllerDistribution Management System

Since MicroGrid is inverter dominated grid it has Inverter control strategies

PQ inverter controlVSI control

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Protection and SafetyIn Traditional distribution system• Power flow is unidirectional• We use over current and Earth fault protection

But in MicroGrid first it should identify whether the fault is inside or outside of MicroGrid

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Environmental AspectsMicroGrid encourages the use of the renewable

energy sources which are environmental friendly

Large land use impacts are avoided

CO2 Emissions are reduced due to the usage of Renewable energy sources

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MicroGrid advantages and disadvantagesAdvantages Disadvantages Ability to disconnect from

utility grid during disturbance and operate independently

It reduces demand on utility grid thus prevents grid failure

We can use both electricity and heat energy so that over all efficiency increases

Voltage ,frequency and power quality should be at acceptable limits

Requires battery tanks to store which requires space and maintenance

Resynchronization to utility grid is difficult

Protection is difficult

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Future scope of ResearchVoltage and frequency control under various

modes of operationProtection schemes for MicroGridTransition between grid connected mode and

island modeTransformation of MicroGrid system today into the

intelligent, robust energy delivery system in the future by providing significant reliability and security benefits

Development of tariff structure for multi MicroGrids

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References “The Rise of MicroGrid Power Networks“

http://www.sustainablefacility.com/Articles/Feature_Article/58905d08bd629010VgnVCM100000f932a8c0

"Why the MicroGrid Could Be the Answer to Our Energy Crisis"http://www.fastcompany.com/magazine/137/beyond-the-grid.html

"How a MicroGrid Works“http://science.howstuffworks.com/microgrid.htm

M. Dicorato,G. Forte,M. Trovato “A procedure for evaluating MicroGrids technical and economic feasibility issues” , IEEE Bucharest Power Tech Conference, June 28th - July 2nd,2009, Bucharest, Romania.

Chem Nayar, Markson Tang, and Wuthipong Suponthana “Wind/PV/Diesel Micro Grid System implemented in Remote Islands in the Republic of Maldives”,IEEE transactions 2008.

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